Re: I imagine that could be a valuable domain
> Guess they must not sell them that way though, because I don't recall ever hearing of .cat previously.
They do not sell it that way. Years ago, well before the "liberalisation" of TLDs, Catalans wanted to have their our ccTLD, but met strong opposition from the Spanish government which refused to add them to the ISO-3166 list of two-letter codes for territorial abbreviations, so they worked on, and eventually got one of the first TLDs aside from .com, .net, .org, .edu, .mil. In this case, .cat is intended for "Catalan-speaking territories and the promotion of Catalan culture" or some such. In reality it works as a (popular) substitute for a ccTLD.
Needless to say, at the time the Spanish government emptied their box of spanners on those guys wheels.